1. Field of the Invention
The present invention relates generally to a bottle mouth defect inspection apparatus and more specifically to a bottle mouth defect inspection apparatus that photo-electrically detects defects in the mouth of a bottle made of glass and the like.
2. Description of the Prior Art
Inspection at a bottle mouth portion of glass bottles or the like is an especially important item among those items of general inspection of glass bottles or the like. The reason is that such defects can cause a very dangerous situation should a human lip touch the bottle mouth and because serious problems are caused by fluid leakage occurring after filling the bottle with fluid and then capping the bottle mouth. Therefore, finest care is taken at the bottle mouth inspection even with new bottles, not to mention recycled bottles that are collected after initial use.
Various types of automatic inspection apparatuses for bottle mouth defects have been proposed in the art. In one of such inspection apparatus light is irradiated onto the bottle mouth portion, and when there is a defect such as a crack or chip at the bottle mouth portion, the irregularly reflected light from such defect portion is received by a photo-electric conversion sensor or the like to thereby sense such defect.
Further, in another one of the prior art inspection apparatus a substantially uniform light irradiation is applied to the top surface portion of the botle mouth, the reflected light from the top surface portion is picked up by a television camera or the like as a doughnut-shaped optical image corresponding to the ensire surface of the bottle mouth top, and then the doughnut-shaped optical image is compared to a standard optical image to thereby detect voids, dropouts or changes in the area, etc. of the doughnut-shaped optical image and hence defects of the bottle mouth.
According to the first of the above mentioned inspection methods there frequently occurs a situation wherein detection becomes difficult due to the fact that depending on the conditions of the cracks or chips at the bottle mouth, the irradiated lights thereon are difficult to be irregularly reflected. In the case of the latter flaw detection method wherein the doughnut-shaped optical image is used, there is a tendency to miss the detection of small flaws due to the fact that the bottles themselves are not precision industrial components and hence the bottle mouth shapes vary rather extensively. As a result it is difficult to set a constant standard for the doughnut-shaped optical image.